I draw a 3" circle at 0,0. And then a 2" circle at 0,-4. I connect a line between the two using a tangent snap.
Then I try to trim the inside curves to leave oblong shape.

Problem shows during trimming. Large circle trims the bottom curve out as expected but leaves a large gap on one side of the curve with the line and curve no longer connected.
Trimming the bottom circle inside curve results in a dialog box saying "Export Failed", then after angrily dismissing the silly dialog, it proceeds to say "Trimming will delete the entire object, Proceed?"

ARG!!!

Hi,

I made sure I was releasing on Tangent as that's what I wanted.
I can recreate the issue very easy, but I did find that if I used "shift to select boundaries" rather than letting tool figure it out, I got the results I wanted.

Is this what you did?

Cheers!